MINERAL MIDTERM Flashcards
1
Q
A
- Pyrite
- FeS2
- Streak is greenish-black
- Conchoidal fracture
- Hardness 6-6.5
- SG is approx 5.1 (heavier than most emtallic minerals)
2
Q
A
- Marcasite
- FeS2
- Streak is greenish to brownish-black
- Sometimes a faintly decectable sulfur smell
- Color is brassy yellow with a greenish tint
- multi-color tarnish may be present
3
Q
Pyrrohotite
A
- Fe(1-x)S (x=0 to 0.2)
- Color is bronze
- Luster is metallic
- Hardness is 3.5 - 4.5
- Streak is grey-black
- Weakly magnetic
4
Q
Covellite
A
- Covellite
- CuS
- Color is deep metallic indigo blue (tarnished purple-black) w/ irridescent flashes of yellow and red
- Cleavage is perfect in one direction forming thin, flexible sheets
- Fracture is flaky
- Hardness is 1.5 - 2
- SG is 4.6 - 4.8
- Streak is grey to black
5
Q
Chalcocite
A
- Cu2S
- Chalcocite
- Color is dark grey to black
- Xtals are usually deeply grooved/striated
- Cleavage is perfect in 2 directions, prismatically
- Fracture is conchoidal
- Hardness is 2.5 - 3
- Streak is shiny black to grey
6
Q
A
- Chalcopyrite
- CuFeS2
- Color is brassy yellow, tarnishes to irridescent blues, greens, yellows, and purples
- Cleavage is rather poor in 1 direction
- Hardness is 3.5 - 4
- Streak is dark green
7
Q
A
- Bornite
- Cu5FeS4
- Color is brown to black with a typical purplish-bluish tarnish, a reddish bronze color on freshly broken surfaces
- Cleavage is very poor
- Fracture is conchoidal
- Hardness is 3
- Streak is grey-black
8
Q
A
- Sphalerite
- (Zn, Fe)S
- Color is typically black but can be brown, yellow, reddish, green, and less commonly white or colorless
- Luster is adamantine or resinous or submetallic to earthy
- Cleavage is perfect in 6 directions forming dodecahedrons
- Fracture is conchoidal but rarely seen
- Hardness 3.5 - 4
- Streak is yellow to light brown
- triboluminescence
- Pyroelectric
9
Q
A
- Galena
- PbS
- Color is lead to silver grey sometimes with a bluish tint
- Habits include cubes, octahedron, and combos
- Cleavage is perfect in 4 directions
- Fracture is uneven
- Hardness 2.5+
- SG is 7.5+ (especially heavy)
- Streak is lead grey
10
Q
A
- Cinnabar
- HgS
- Color is bright scarlet or cinnamon red to a brick red
- Luster is adamantine to submetallic
- Hardness is 2 - 2.5
- SG is 8.1+ (especially heavy for non-metallic mineral)
- Habits are rarely individual xtal, commonly crusts and massive
11
Q
A
- Realgar
- As4S4
- Color is orange to red
- Luster is resinous, adamantine, to submetallic
- Cleavage is good in 1 direction
- Hardness is 1.5 - 2
- Streak is orange-yellow
- Unstable in light
- Almost always inclue orpiment
12
Q
A
- Orpiment
- As2S3
- Color is orange-yellow to yellow
- Hardness is 1.5 - 2
- Streak is yellow
- Unstable in light
- Distinct odor similar to sulfur but due to the aresenic
13
Q
A
- Stibnite
- Sb2S3
- Color is steel grey to silver
- Luster is metallic
- Cleavage is perfect in lengthwise direction
- Streak is dark grey
- Striated lengthwise
- Slightly flexible xtals
14
Q
A
- Molybdenite
- MoS2
- Color is silver metallic with a bluish cast
- Luster is metallic
- Cleavage is perfect in 1 direction, forming sheets
- Fracture is flaky
- Hardness is 1.5 - 2
- Streak is bluish grey
15
Q
A
- Arsenopyrite
- FeAsS
- Color is brassy white to grey
- Luster is metallic
- Hardness is 5.5 - 6
- SG is approx 6.1 (slightly heavier than usual)
- Bitter smell when powdered or broken
16
Q
A
- Tetrahedrite
- (Cu, Fe)12Sb4S13
- Color is black to steel grey to silver
- Luster is metallic
- No cleavage
- Fracture is conchoidal
- Hardness is 3 - 4+
- Tarnishes to greenish shade
17
Q
A
- Kernite
- Na2B4O6(OH)2 3H2O
- Color is colorless to white
- Luster is vitreous to pearly
- Cleavage is perfect in 2 directions
- Fracture is splintery due to cleavage
- SG is 1.9 (very low density)
- Streak is white
18
Q
A
- Borax
- Na2[B4O5(OH)4] 8H2O
- Color is white
- Luster is dull/earthy
- Cleavage is perfect in 1 direction
- Fracture is conchoidal
- Hardness is 2 - 2.5
- SG is 1.7 (very light density)
- Streak is white
- Sweet alkaline taste